Anchor bolt assembly and utilization

ABSTRACT

A pull-up bolting assembly is constructed to be inserted endwise and rotatably advanced as a unit within a bore hole of a rocklike roof or other structure, with the forward end of the assembly being employed to fracture an in-placed, adhesive resin material containing capsule, and to mix the adhesive material and force it about a hollow pipelike anchor member of the assembly and along the spacing between it and the bore hole. After the adhesive material has set or hardened about the hollow anchor member to non-rotatably fix it in position within a back end portion of the bore hole, a stop means is sheared by a bolt member of the assembly which is then relatively rotatably advanced within a resin-clear, front portion of the bore hole into and along the hollow anchor member until a bearing plate of the assembly is tension-held by the bolt against an outer face of the rock-like structure.

[4 1 Apr. 15, 1975 ANCHOR BOLT ASSEMBLY AND UTILIZATION [75] Inventor:David H. Hill, Clarksburg, W. Va.

[73] Assignee: West Virginia Bolt Inc., Clarksburg,

W. Va.

[22] Filed: Nov. 28, 1973 [21] Appl. No.: 419,644

[52] U.S. Cl. 61/45 B; 52/698 [51] Int. Cl. F2ld 20/02 [58] Field ofSearch 6l/63, 45 B; 52/698, 704; 85/63, 75

[56] References Cited UNITED STATES PATENTS 2,829,502 4/1958 Dempsey52/704 X 2,952,129 9/1960 Dempsey 61/45 B 3,108,443 10/1963 Schuermannet a1. 52/698 X 3,618,326 11/1971 Montgomery 61/45 B 3,702,060 11/1972Cumming 61/45 B FOREIGN PATENTS OR APPLICATIONS 1,268,624 6/1961 France61/45 B 955,678 l/1957 Germany 61/45 B Primary E.taminerDennis L. TaylorAttorney, Agent, or FirmParmelee, Miller, Welsh & Kratz [57] ABSTRACT Apull-up bolting assembly is constructed to be inserted endwise androtatably advanced as a unit within a bore hole of a rock-like roof orother structure, with the forward end of the assembly being employed tofracture an in-placed, adhesive resin material containing capsule, andto mix the adhesive material and force it about a hollow pipelike anchormember of the assembly and along the spacing between it and the borehole. After the adhesive material has set or hardened about the hollowanchor member to non-rotatably fix it in position within a back endportion of the bore hole, a stop means is sheared by a bolt member ofthe assembly which is then relatively rotatably advanced within aresin-clear, front portion of the bore hole into and along the hollowanchor member until a bearing plate of the assembly is tension-held bythe bolt against an outer face of the rock-like structure.

20 Claims, 6 Drawing Figures PATENTEUAPR 1 m Fig. 4

III"lllllilliliiilililiii i IN I Fig. 2

Fig. 6

Fig. l

ANCHOR BOLT ASSEMBLY AND UTILIZATION BACKGROUND OF THE INVENTION 1.Field of the Invention This invention pertainstoaa new and improvedpullup bolting assembly which is particularly designed for use instrengthening mine roofs and also, to a bolting assembly that is adaptedto effectively utilize a minimized amount of quick setting adhesive,grout or cement within a bore hole that extends from a face of arock-like structure. A phase of the invention deals with a boltingassembly having means for enabling it to be rotatably endwise introducedinto a bore hole as a unit and, after a hollow anchor member of theassembly has been secured therein by an adhesive material, forthereafter utilizing a bolt element of the assembly to finalize itsinstallationas a tensioned unit.

2. Description of the Prior Art Over the years, two approaches have beenmade in providing so-called anchor bolts, such as may be used forstrengthening roofs in a coal mine, a subway tunnel, etc. An older typeof construction employs parts that can be expanded on insertion within adrill or bore hole to provide a mechanical type of expansion grippingaction, to thus permit a bolt or screw to be tighteneddown against aface of the rock structure. It is important to provide a boltingassembly that will enable a tension pull-up or tightening-down of a boltand bearing plate assembly under present day Bureau of Mines standards.The Bureau of Mines requires that such a unit be capable of assuringthat the installed bolt tension be within a range of 6 to 8,000 pounds.

A second and more recent type of assembly makes use of adhesive orgrouting material within and substantially along a drill or bore holefor securing a rod or bolt in place; if a pull-up tensioning is desired,the outer end of the rod or bolt is threaded and provided with a nut andface plate washer. The nut may be tightened-down to, in effect, pull-upthe plate against the front face of the structure.

The mechanical type has not been too satisfactory in view of the factthat it requires a relatively strong or more stable type of stratum andmany different types of formations are encountered, such as (l) mudstoneor siltstone, (2) limestone or massive sandstone, and (3) laminatedsandstone or shales. Where adhesive materials have been used for boltanchorage, bonding strengths have ranged from 1,200 lbs/ linear inch (l/4 inch hole diameter) for 1) above, to 4,000 lbs/inch for (2) and 2,000lbs/inch for (3). However, difficulty has been encountered inendeavoring to provide a better type that will have a maximum tensilestrength in its utilization and without excessive cost. The second oradhesive type has the advantage that the adhesive may be employed tostrengthen the particular rock formation as well as to secure the boltin position therein. However, an assembly of the latter type has beenrather expensive and requires considerable amount of adhesive in thatthe idea has heretofore been to substantially fill the hole about thefull length of the rod or bolt member, as positioned to extendsubstantially along the full length of the drill hole. The drillhole,.depending on the type of rock formation or stratum, usually has adepth of about 2 to 5 feet, but in some cases has gone to a depth ofabout 12 feet.

There has been a need for an improved type of bolting assembly whichwill make possible a maximized amount of face compression and drawuptension strength in its installation, and, at the same time, which willbe relatively inexpensive from the standpoint of time and materials. Asto the cost of installation, it is important to minimize the timerequired for the setting or hardening of the adhesive material withinthe drill hole, in order that the bolt tensioning portion of theoperation may be quickly accomplished to complete the installation. Thepresent invention makes possible the employment of an assembly of thesecond type that can be provided and installed at a relatively low cost,with a maximized economy as to the adhesive, and that will have anessential strength in installation.

SUMMARY OF THE INVENTION It has thus been an object of the presentinvention to devise a new and improved type of pull-up bolting assemblythat may be used for mine roof and other installations wherein a strongand stable structure may be attained.

Another object of the invention has been to evaluate the factorsinvolved and devise a new approach to the fixing ofa bolting assemblywithin a rock-like structure.

A further object has been to devise new procedure in roof strengtheningand in rock-like formation securing which will enable a material savingof cost.

A still further object has been to devise a bolting assembly which willminimize quantity requirements for an adhesive material, will enable theuse of the adhesive material in such a manner as to minimize the timeelement in effecting its curing, setting or hardening, and will enablean effective relative movement between parts of the assembly when aninner part has been secured in position by the adhesive and, at the sametime, will enable a forwardly advancing rotation of the assemblyinitially as a unit during its insertion into the bore hole of arock-like structure.

These and other objects of the invention will appear to those skilled inthe art from the illustrated embodiments and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings,

FIG. 1 is a vertical section in elevation showing the construction of abolting hole assembly constructed in accordance with the invention, andalso showing an initial step in its utilization. In this view, anenclosed sealed-off capsule containing a main body of adhesive resinmaterial and a segregated content of a catalyst, hardening or curingresin material, both in liquid or somewhat viscous form, has been fullyinserted into a drill hole; a bolting assembly of the invention has beenthereafter inserted into the hole and with its back end in engagementwith a forward end of the adhesive capsule, preliminarily to fracturingthe capsule for releasing and mixing the materials therein.

FIG. 2 is a view on the scale of and similar to FIG. 1, but showing asecond step in a utilization of the assembly of the invention in which ahollow, pipe-like, anchor member has been rotatably advanced within thehole by a unitized, rotative endwise advance of the bolting assembly,with the hollow member being employed to not only fracture the adhesivecapsule but to mix its contents and force them as in a mixed conditionabout and along the full extent of such member.

FIG. 3 is a view similar to and on the scale of FIGS. 1 and 2,illustrating a third step of the operation which is effected after theadhesive material has set or hardened to secure the hollow anchor memberin a nonrotatable fixed position within the bore hole, and a headed boltis advanced relative to the fixed anchor member by employing an end ofits threaded stem to break-through or penetrate a front end wall orclosure disc of the hollow anchor member. Thereafter, the bolt isscrew-advanced until its bearing plate has been pulled-up into tightabutment with the face of the rock structure and into a coveringrelation with respect to the hole therein.

FIG. 4 is a slightly enlarged fragmental side perspective view showingdetails of the construction of a back end wall of the hollow member ofthe construction which serves as a cutting and mixing means for theadhesive material.

FIG. 5 is a similar view on the scale of FIG. 4, illustrating a modifiedtype of back end wall having a chisel edge and which may be in the formof a plug-like element or a cap.

And, FIG. 6 is a fragmental side perspective view on the scale of FIGS.4 and 5 illustrating a preferred simplified construction of the frontend of the hollow member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In carrying out the invention,an adhesive resin capsule, cartridge or sausage 30 is shown, since aquick setting type of resin material can be very effectively utilized.It has been discovered that, contrary to previous ideas, it is notnecessary to distribute or provide an adhesive material of a quantitysufficient to substantially fully fill the depth extent of the bore ordrill hole and about the bolt assembly employed therein. In accordancewith the present invention, the length of adhesive material isproportioned to an amount sufficient to, as shown in FIG. 2, fill in thespacing between the innermost end of the hole and a back end of andfully along the extent of a hollow, pipe or shell anchor member 16. Themember 16 may be an inexpensive piece of hollow material, such as alength of ordinary steel pipe and is preferably provided with aroughened or cross-hatched outer surface that may be rolled thereon toassure a maximum adherence between it and the adhesive materialemployed. However, it has been determined that the bond between theresin matrix and bore hole surface is more important than the bondbetween the resin and the hollow anchoring member.

In evaluating the factors involved in providing an installation thatwill have sufficient strength, both from the standpoint of tension andcompression, it was determined that as little as a 5 inch length of anordinary steel pipe member of about 1 inch in outer diameter, utilizedin the manner shown in FIG. 2, within a bore hole 11 of about1%11'161'168 in diameter, will provide a holding strength of at leastabout 22,000 lbs. in a limestone ,or massive sandstone structure. Theamount of adhesive resin material may be minimized for each type ofstratum or strata structure, and the time required in curing, setting oreffecting a hardening of the material may be minimized to effect amaterial saving in the overall cost of each installation. For example,using a quick-setting resin material 30, such as a polyester, andemploying the bolt construction 15 illustrated, it is now possible tomake a complete installation within 1 minute from the time of theinitial insertion of the bolting assembly as a unit within a bore ordrill hole 11. The mixing. setting or hardening of the mixed resinmaterial involves a matter of a few seconds.

Using a 1% to 1% inch bore or drill hole diameter and a l to 1% outerdiameter of pipe member 16, successful use has been made of pipe memberlengths of about 6 to 8 inches. However, it has been determined thatabout a 6 inch length of anchoring pipe or head member 16 is a goodaverage length that provides a full safety margin where the unit orassembly is to be installed in ordinary rock strata. However, the lengthmay be increased for unstable, soft rock as may be required. Byutilizing a short length amount of adhesive material, cartridge orcapsule, a saving of about 25 cents per foot of bolt length may beeffected with the hardening or setting being accomplished within amatter of about a minute, as distinguished from about 2 minutes,utilizing a full hole-filling length of old type or group of resincartridges. The strength attained will equal or exceed the strength ofthe bolt, with a material saving in cost and a 50 percent reduction ininstallation time.

For very soft shales, a greater length of about 18 to 24 inches may beused, but it has been determined that lengths of 6 to 8 inches aregenerally sufficient, utilizing an 80,000 psi high tension steel boltwith a diameter of anchor shell of about 1 inch with a 1% or 1% inchbore hole. To maximize holding of the anchor pipe member 16, it may begiven a light side blow to form it into a slightly oval or ellipsoidshape.

Referring to the drawings, 10 represents a rock-like wall or supportstructure which is to be secured together or reinforced and which isprovided with a bore or drill hole 11 for receiving a bolting .assemblyof the invention. The assembly has a forward, somewhat cylindrical,pipe-like hollow member, shell or part 16 that constitutes an anchor forthe construction. Opposite open ends of the hollow member 16 areclosed-off by back and front end walls 17 and 18, such as may beprovided by small, stamped-out, disc-like parts or.

pieces of a metal such as steel, that may be electrically resistance orinduction welded to the pipe member.

The back end wall 17, as shown in FIG. 4, is provided with a pair ofupset portions 17a along its outer edge that serve as breaking andcutting edges as well as a mixing means for the adhesive resincontaining capsule 30. To save expense, the element or piece 17 may bestamped-out at 17a and then secured by weld metal w to the back end ofthe pipe member 16. The width of each portion 17a may substantiallyconform to the wallthickness of the pipe member 16, so that a fullsealingoff may be easily accomplished by securing the piece 17 inposition by a weld w over the back end of the associated pipe member. Afront metal disc 18 may also be secured by electric resistance orinduction welding to the front end of the member 16 to fully close itoff.

As shown in FIGS. 1, 2 and 3, a standard nut 20, such as a hexagonal nutelement, is secured by weld metal w, directly on the front face of thefront disc or closure wall 18 to project forwardly therefrom. A bolt,bar or rod 15, headed with a wrench fiat, is provided having a stem 23which is of a length equal to the distance between the front end wall 18of the pipe member 16 in its in-place secured position of FIG. 2 and theouter face of the drill hole. The stem 23 is threaded at its backwardlyextending end portion to turnably or rotatably fit within the nut 20 andto later shear the end wall l8 and advance past the nut into the hollowanchor member 16 (see FIG. 3).

During an initial insertion of the bolting assembly into the drill hole11, the stem 23 of the bolt 15 has its back end portion 230 (see FIG. I)in tight abutment with the front face of the closure wall or disc member18. Thus, the entire assembly may be inserted and rotatably advancedendwise as a unit within the drill hole 11, and such rotative inwardinsertion continued until the bolt head and its bearing plate 25 hasmade contact with the face of the rock structure 10 thereby preventingfurther insertion of the assembly as shown in FIG. 2. A pneumatic orother suitable form of power tool may be applied to a head 24 of thebolt for this purpose.

At this time, a short wait of, for example, 60 seconds will enable thematerial to cure, harden or set about the pipe member 16 to anchor orsecure it non-rotatably within the end of the drill hole 11. Thereafter,the bolt 15 is screw or turnably advanced by again applying rotativeforce to the head 24 to thereby cause a backward end portion 23a of thebolt 15 to displace, shear or fracture and penetrate the relatively thinwall thickness of the front disc or end wall member 18. The relativemovement of the bolt 15 with respect to the anchored pipe member 16 iscontinued until, as shown in FIG. 3, the bolt 15 has advanced within thepipe member sufficiently to bring its head 24 into tension tocompressionhold its associated bearing plate or enlarged washer 25against the front face of the rock formation and closeoff the bore hole11.

In FIG. 5, a modified form of back end wall 26 is illustrated which isin the form of a plug that may be electrical induction orresistance-welded at w to extend from within the back end of the pipemember 16. The end wall 26 terminates in a central, wedge-shaped edgeportion 26a centrally to provide a chisel-like cutting and mixing pairof surfaces for the adhesive resin material.

With reference to FIG. 1, a typical adhesive capsule or cartridge 30consists of a main body of resin material 31 and a segregatedsupplemental body of a catalyst, curing or hardening resin 32. Bothresins are retained in the capsule or cartridge by means of a relativelythin wall resin bag or sausage of any suitable type that is easilyruptured or broken by the rotative advance of the forward end wall 17 or26 of the shell member 16 which becomes an anchoring part or member whenthe mixed resin material has hardened or set. The resin material 32 isused for polymerizing, curing and setting the main body of the resinmaterial 31 when they are mixed together and displaced along the borehole 11 and about the pipe member 16 up to a sealing gasket 19.

In order to conserve the adhesive material, avoid clogging threads ofthe screw assembly and limit movement of the adhesive to the full extentof the outer periphery of the hollow member 16, the sealing gasket 19,shown of a rubberlike O-ring type, is mounted about the outer peripheryof the hollow member 16 adjacent its front end and in seated, forward,position-limited abutment with a radially outwardly extending flangeportion of the front end wall 18. The gasket 19 will have a largerdiameter than the drill or bore hole 11 such that it is slightlycompressed when inserted within the hole.

The requisite length of anchoring shell, pipe or hollow head member 16may be checked by pull tests to determine its anchorage strength, whichneed not be more than the minimum breaking load for the bolt 15. Astandard mine roof bolt of five/eighths of an inch in diameter willyield at a load between 9,700 to [4,700 lbs. and fail between aboutl6,200 and 24,600 lbs. Celtite, Inc. of Cleveland, Ohio and DuPont ofWilmington, Del. are two representative companies that are in a positionto supply the resin cartridges or capsules, and which can be mixed andcured under rotation of at least 120 rpm. within about to 75 secondswhere the starting resin temperature is within a range of about to F orat usual mine temperature (of about 68 F). The nut 20 may be aconventional hex nut for a bolt 15 of about five/eighths of an inch indiameter. The length of the bolt-anchor assembly from back end wall 17to bearing plate 25, ideally, should be equal to or slightly less thanthe depth of the bore hole. However, the bolt take-up during tensioningwill compensate for an under-depth bore hole.

In accordance with the present invention, itihas been definitelydetermined that full length resin encapsulation is not necessary, anddepending on theparticular rock or roof formation, that, using a sleeveor pipe member, a resin grouting length of about 6 to 8 inches issufficient. For example, using an anchoring sleeve member 16 having anouter diameter of about 1% inches within a bore hole of about 1% inches,provides a one/eighth of an inch spacing width within which the resinmaterial will provide a matrix layer or encapsulation. Such spacingshould preferably be within a range of about one/sixteenth tothree/sixteenths of an inch on the side with an optimum of aboutone/eighth inch. The full strength of the main resin body 31 requires agood or thorough mixing with the catalyst or hardening resin 32. Arotational speed of at least rpm. has been found to be satisfactory,although the extremely fast setting resins to be used with this deviceshould be mixed at maximum speed (about 475 rpm). The working face ofthe average coal mine has been found to have a temperature of about 68 Fwhich requires a total time of mixing-curing of about 60 to 75 seconds.

Although, as above pointed out, a device of the invention isparticularly suitable for mine roof usage, it also may be employed intunnels, and for tieingtogether rock-like pieces, such as foundationstone, etc. It enables obtaining the full tensile strength of the bolt,with minimal loss of tension due to subsequent weathering anddeformation of the anchor rock, that is competitive with a so-calledmechanical expansion type of unit. It eliminates the need for an easilydamaged and loose nut on a threaded rod or bolt such as used with a typein which the rod or bolt is, itself, directly resin or grout anchored inplace substantially fully along its length extent within a bore hole.

FIG. 6 shows a simplified and optimum construction of the front end ofthe hollow member 16 in which front metal disc 18 has a smaller diametersuch that it will fit therewithin, and the nut 20 has an effectivediameter such that its outer edge portion or at least its corners serveas position-limiting abutment or shoulder means for the gasket 19. Thisenables a direct welding of the nut 20 on the front end of the hollowmember 16.

disc 18' is penetrated and ruptured when the bolt is later advanced fortensioning.

I claim:

l. A roof bolting assembly for mounting in position within a bore holeof a mine roof that is to be strengthened which comprises, a hollow pipeanchor member of a shorter length than the depth of the bore hole, adestructible capsule that contains quick-setting adhesive resin andcatalyst-hardener resin materials for insertion into a back end of thebore hole, a headed bolt having a threaded stem and an associatedwide-face bearing plate, front and back closure walls at opposite endsof said anchor member, a threaded nut secured to a front end of saidanchor member to rotatably receive a back end of said threaded stemtherein, said bolt being initially limited in its positioning withinsaid nut by endwise-abutment of the back end of said stem against saidfront closure wall, said anchor member and said bolt as assembled in thedefined manner being adapted to be endwise-inserted and rotatablyadvanced within the hole until said back closure wall engages andfractures said capsule and mixes and distributes the resin materialcontent thereof within the bore hole from its back end and forwardlyalong said anchor member, sealing means carried by said anchor memberfor preventing the mixed resin material from advancing along the borehole beyond said front closure wall, said mixed resin material beingadapted to quickly set within the bore hole and to thereby non-rotatablysecure said anchor member therein, and said stem of said bolt beingthereafter adapted to be turned within said nut to fracture andpenetrate said front closure wall and advance relative to and withinsaid anchor member until said bolt is drawn-up and tensioned to holdsaid bearing plate in tight engagement with the front face of the roofabout the bore hole therein.

2. A roof bolting assembly as defined in claim 1 wherein said back andfront closure wall are separate pieces that are welded to the front andback ends of said anchor member, and said sealing means is a ringlikegasket positioned about said anchor member adjacent to said frontclosure wall.

3. A roof bolting assembly as defined in claim I wherein, said frontclosure wall is a relatively thin piece of metal that is secured withinthe front end of said anchor pipe member and that is easily fractured bya backward advance of said bolt within said nut when said anchor memberhas been secured by the setting of the resin material thereabout withinthe bore hole.

4. A mine roof bolting assembly as defined in claim 1 wherein said backclosure wall has at least one backwardly projecting portion forfacilitating fracturing said capsule and the mixing of its resinmaterial content.

5. A mine roof bolting assembly as defined in claim 4 wherein saidbackwardly projecting portion is a chisel-like edge.

6. A mine roof bolting assembly as defined in claim 1 wherein said backclosure wall has a spaced-apart pair of upset projections adjacent itsouter periphery that substantially correspond in width to the wallthickness of said anchor member.

7. A roof bolting assembly as defined in claim 1 wherein, said frontclosure wall is a thin metal disc having a peripheral flange portionprojecting beyond the outer periphery of said anchor member to provide aseating shoulder for said sealing means, and said sealing means is aring-like gasket encircling the outer wall of said anchor member andresting in abutment with said flange portion.

8. A bolting assembly for mounting in position within a bore holeextending inwardly from the face of a rocklike structure such as a mineroof and that is adapted to be secured in position within the bore holeby an adhesive material that has been placed within the bore hole whichcomprises, a cavity defining longitudinal extending metal anchor memberof shorter length than the depth of the bore hole and adapted to beintroduced into the bore hole and pressed into the adhesive material andto be thereafter non-rotatably secured in position therein by ahardening of the adhesive material thereabout, a bolt having a threadedstem and an associated washerlike bearing plate that is adapted to restagainst the face of front part of the structure to closeoff the borehole therein, a threaded nut centrally secured over the cavity to thefront end of said anchor member and adapted to rotatably receive a backend of the threaded stem of said bolt therein, stop means cooperatingwith said nut for limiting the amount of insertion of the threaded stemtherewithin until said anchor member has been secured in position withinthe bore hole by the adhesive material, said stop means being adapted tobe thereafter sheared by a rotational advance of said bolt within saidnut into the cavity, so that said bolt can be fully advanced intotension-holding engagement with the face of the structure through theagency of said bearing plate.

9. A bolting assembly as defined in claim 8 wherein said stop means isan end closure disc secured in position between a front end of saidanchor member and a back end of said nut.

10. A bolting assembly as defined in claim 9 wherein, said closure discis a metal member of relatively thin wall construction, said closuredisc has a flange portion extending radially outwardly beyond thediameter of said anchor member, and a gasket is positioned on said pipemember against said flange portion for engaging the bore hole andrestricting outward flow of the adhesive material to the length of saidanchor member.

11. A roof bolting assembly as defined in claim 8 wherein, a ring-likegasket is carried by a front end portion of said anchor member forsealing-off the joint between the bore hole and said member duringsetting of the adhesive material within the bore hole, the outer surfaceof said anchor member is roughened to facilitate adherence of theadhesive material thereto, and said anchor member has a usual lengthfrom end to end of about 6 to 8 inches and has an outer diameter ofabout 1 to 1% inches.

12. A roof bolting assembly as defined in claim 8 wherein, said nut isdirectly secured on a front end portion of said anchor member, said stopmeans is a closure wall secured over a back end of said nut, said nuthas an outer periphery that extends radially beyond the outer peripheryof said anchor member, and a ring-like gasket is carried on a front endportion of said anchor member in forwardly limited abutment with theouter periphery of said nut.

13. A method of reinforcing a mine roof having a rock-like constructionwhich comprises, boring an elongated hole into the roof from an outerface thereof; providing a bolting assembly of a pipe-like hollow anchormember having a cross-extending back end wall and a fracturableclosed-off front end wall portion, having a nut secured to the front endwall portion and projecting forwardly therefrom and having a headed boltcarrying a bearing plate and with its threaded end mounted within thenut for endwise abutment with the front end wall; first inserting aquick-setting resin adhesive material contained within a thin skin resincapsule into the inner end of the bore hole, inserting the boltingassembly endwise as non-rotatably unit into the bore hole with the backend wall of the pipe member in engagement with the capsule. rotating thebolting assembly and employing the back end of the anchor member torupture the skin of the capsule and mix its resin material content,flowing the mixed resin material about and between the outer peripheryof the anchor member and the inner periphery of the bore hole andrestricting its forward flow to substantially the length of the anchormember during the rotative advance of the bolting assembly, hardeningthe mixed resin material about the anchor member to nonrotatably secureit within the bore hole, rotatably advancing the bolt by turning it withrespect to the anchor member within the nut and fracturing the front endwall portion, and then advancing the bolt within the anchor member anddrawing the bearing plate into tight abutment against the outer face ofthe roof over the bore hole by tightening the bolt under tension withinthe nut.

14. A method as defined in claim 13 wherein an an nular width of spacingwithin a range of about onesixteenth to one/eighth of an inch ismaintained between the inner diameter of the bore hole and the outerdiameter of the anchor member within which the resin material ishardened.

15. An improved anchor bolting assembly for mounting in position withina hole extending from a face of and into a support structure and that isadapted to be secured in position within the hole by an adhesivematerial placed therein which comprises, a longitudinally extendinganchor member adapted to be introduced into the hole and having a backend portion for movement into the adhesive material therein, said anchormember being adapted to be thereafter secured in position by hardeningof the adhesive material thereabout, a headed bolt having a threadedstem and carrying a bearing plate member thereon that is adapted to restagainst a face of the front part of the structure to close-off the holetherein, threaded nut-like means secured on a front end of said anchormember and adapted to receive a back end of said stem therein, meanscarried by the front end of said anchor member to initially limit theadvance of said stem within said nut-like means when said anchor memberis being inserted into the hole and to thereafter fracture underrotational advance of an end portion of said stem within said nut-likemeans and with respect to said anchor member when said anchor member hasbeen secured in position within the hole by the adhesive material, sothat said bolt can be advanced into holding engagement with the face ofthe support structure through the agency of said bearing plate member.

16. An improved anchor bolting assembly as defined in claim 15 whereinflange means is positioned about a forward end portion of said anchormember and extends radially outwardly beyond the outer periphery of saidanchor member.

17. An improved anchor bolting assembly as defined in claim 16 wherein aring-like gasket is carried on the front end portion of said anchormember in forwardly limited abutment with said flange.

18. An improved anchor bolting assembly for mounting in position withina hole extending from a front face of and into a support structure andthat is adapted to be secured within the hole by an adhesive materialcarried within a destructible capsule that has been placed therein whichcomprises, a longitudinally extending pipe-like anchor member havingmeans closing-off its back end, a headed bolt having a threaded sternand carrying a bearing plate thereon, threaded nut-like means carried ona front end portion of said anchor member and adapted to rotatablyreceive a forward end of said stem therein, stop means carried by thefront end portion of said anchor member to initially limit turningadvance of said stem within said nut-like means and with respect to saidanchor member when said anchor member is being inserted within the hole,said closing-off means being adapted to move into pressure engagementwith the capsule to fracture it and force the adhesive material alongthe outer side of the length of said anchor member when said anchormember is introduced into the hole by said threaded stem, said anchormember being adapted to be secured in position within the hole by theadhesive material, and said stop means being adapted to thereafter bedisplaced under relative rotational backward advancement of said sternwithin said nut-like means whereby said bearing plate may be moved intoholding engagement with the front face of the support structure.

19. An improved anchor bolting assembly as defined in claim 18 whereinmeans is carried by the front end portion of said anchor member forconfining flow of the adhesive material to substantially the length ofsaid anchor member.

20. An improved anchor bolting assembly as defined in claim 19 whereinsaid closing-off means has means for facilitating penetration of thecapsule.

1. A roof bolting assembly for mounting in position within a bore holeof a mine roof that is to be strengthened which comprises, a hollow pipeanchor member of a shorter length than the depth of the bore hole, adestructible capsule that contains quick-setting adhesive resin andcatalyst-hardener resin materials for insertion into a back end of thebore hole, a headed bolt having a threaded stem and an associatedwide-face bearing plate, front and back closure walls at opposite endsof said anchor member, a threaded nut secured to a front end of saidanchor member to rotatably receive a back end of said threaded stemtherein, said bolt being initially limited in its positioning withinsaid nut by endwise-abutment of the back end of said stem against saidfront closure wall, said anchor member and said bolt as assembled in thedefined manner being adapted to be endwise-inserted and rotatablyadvanced within the hole until said back closure wall engages andfractures said capsule and mixes and distributes the resin materialcontent thereof within the bore hole from its back end and forwardlyalong said anchor member, sealing means carriEd by said anchor memberfor preventing the mixed resin material from advancing along the borehole beyond said front closure wall, said mixed resin material beingadapted to quickly set within the bore hole and to thereby non-rotatablysecure said anchor member therein, and said stem of said bolt beingthereafter adapted to be turned within said nut to fracture andpenetrate said front closure wall and advance relative to and withinsaid anchor member until said bolt is drawn-up and tensioned to holdsaid bearing plate in tight engagement with the front face of the roofabout the bore hole therein.
 2. A roof bolting assembly as defined inclaim 1 wherein said back and front closure wall are separate piecesthat are welded to the front and back ends of said anchor member, andsaid sealing means is a ring-like gasket positioned about said anchormember adjacent to said front closure wall.
 3. A roof bolting assemblyas defined in claim 1 wherein, said front closure wall is a relativelythin piece of metal that is secured within the front end of said anchorpipe member and that is easily fractured by a backward advance of saidbolt within said nut when said anchor member has been secured by thesetting of the resin material thereabout within the bore hole.
 4. A mineroof bolting assembly as defined in claim 1 wherein said back closurewall has at least one backwardly projecting portion for facilitatingfracturing said capsule and the mixing of its resin material content. 5.A mine roof bolting assembly as defined in claim 4 wherein saidbackwardly projecting portion is a chisel-like edge.
 6. A mine roofbolting assembly as defined in claim 1 wherein said back closure wallhas a spaced-apart pair of upset projections adjacent its outerperiphery that substantially correspond in width to the wall thicknessof said anchor member.
 7. A roof bolting assembly as defined in claim 1wherein, said front closure wall is a thin metal disc having aperipheral flange portion projecting beyond the outer periphery of saidanchor member to provide a seating shoulder for said sealing means, andsaid sealing means is a ring-like gasket encircling the outer wall ofsaid anchor member and resting in abutment with said flange portion. 8.A bolting assembly for mounting in position within a bore hole extendinginwardly from the face of a rock-like structure such as a mine roof andthat is adapted to be secured in position within the bore hole by anadhesive material that has been placed within the bore hole whichcomprises, a cavity defining longitudinal extending metal anchor memberof shorter length than the depth of the bore hole and adapted to beintroduced into the bore hole and pressed into the adhesive material andto be thereafter non-rotatably secured in position therein by ahardening of the adhesive material thereabout, a bolt having a threadedstem and an associated washerlike bearing plate that is adapted to restagainst the face of front part of the structure to close-off the borehole therein, a threaded nut centrally secured over the cavity to thefront end of said anchor member and adapted to rotatably receive a backend of the threaded stem of said bolt therein, stop means cooperatingwith said nut for limiting the amount of insertion of the threaded stemtherewithin until said anchor member has been secured in position withinthe bore hole by the adhesive material, said stop means being adapted tobe thereafter sheared by a rotational advance of said bolt within saidnut into the cavity, so that said bolt can be fully advanced intotension-holding engagement with the face of the structure through theagency of said bearing plate.
 9. A bolting assembly as defined in claim8 wherein said stop means is an end closure disc secured in positionbetween a front end of said anchor member and a back end of said nut.10. A bolting assembly as defined in claim 9 wherein, said closure discis a metal member of relatively thin wall construction, said closuredisc has a flange portion extending radially outwardly beyond thediameter of said anchor member, and a gasket is positioned on said pipemember against said flange portion for engaging the bore hole andrestricting outward flow of the adhesive material to the length of saidanchor member.
 11. A roof bolting assembly as defined in claim 8wherein, a ring-like gasket is carried by a front end portion of saidanchor member for sealing-off the joint between the bore hole and saidmember during setting of the adhesive material within the bore hole, theouter surface of said anchor member is roughened to facilitate adherenceof the adhesive material thereto, and said anchor member has a usuallength from end to end of about 6 to 8 inches and has an outer diameterof about 1 to 1 3/8 inches.
 12. A roof bolting assembly as defined inclaim 8 wherein, said nut is directly secured on a front end portion ofsaid anchor member, said stop means is a closure wall secured over aback end of said nut, said nut has an outer periphery that extendsradially beyond the outer periphery of said anchor member, and aring-like gasket is carried on a front end portion of said anchor memberin forwardly limited abutment with the outer periphery of said nut. 13.A method of reinforcing a mine roof having a rock-like constructionwhich comprises, boring an elongated hole into the roof from an outerface thereof; providing a bolting assembly of a pipe-like hollow anchormember having a cross-extending back end wall and a fracturableclosed-off front end wall portion, having a nut secured to the front endwall portion and projecting forwardly therefrom and having a headed boltcarrying a bearing plate and with its threaded end mounted within thenut for endwise abutment with the front end wall; first inserting aquick-setting resin adhesive material contained within a thin skin resincapsule into the inner end of the bore hole, inserting the boltingassembly endwise as non-rotatably unit into the bore hole with the backend wall of the pipe member in engagement with the capsule, rotating thebolting assembly and employing the back end of the anchor member torupture the skin of the capsule and mix its resin material content,flowing the mixed resin material about and between the outer peripheryof the anchor member and the inner periphery of the bore hole andrestricting its forward flow to substantially the length of the anchormember during the rotative advance of the bolting assembly, hardeningthe mixed resin material about the anchor member to nonrotatably secureit within the bore hole, rotatably advancing the bolt by turning it withrespect to the anchor member within the nut and fracturing the front endwall portion, and then advancing the bolt within the anchor member anddrawing the bearing plate into tight abutment against the outer face ofthe roof over the bore hole by tightening the bolt under tension withinthe nut.
 14. A method as defined in claim 13 wherein an annular width ofspacing within a range of about one-sixteenth to one/eighth of an inchis maintained between the inner diameter of the bore hole and the outerdiameter of the anchor member within which the resin material ishardened.
 15. Am improved anchor bolting assembly for mounting inposition within a hole extending from a face of and into a supportstructure and that is adapted to be secured in position within the holeby an adhesive material placed therein which comprises, a longitudinallyextending anchor member adapted to be introduced into the hole andhaving a back end portion for movement into the adhesive materialtherein, said anchor member being adapted to be thereafter secured inposition by hardening of the adhesive material thereabout, a headed bolthaving a threaded stem and carrying a bearing plate member thereon thatis adapted to rest against a face of the front part of the structure toclose-off the hole therein, threaded nut-like means secured on a frontend of said anchor member and adapted to receive a back end of said stemtherein, means carried by the front end of said anchor member toinitially limit the advance of said stem within said nut-like means whensaid anchor member is being inserted into the hole and to thereafterfracture under rotational advance of an end portion of said stem withinsaid nut-like means and with respect to said anchor member when saidanchor member has been secured in position within the hole by theadhesive material, so that said bolt can be advanced into holdingengagement with the face of the support structure through the agency ofsaid bearing plate member.
 16. An improved anchor bolting assembly asdefined in claim 15 wherein flange means is positioned about a forwardend portion of said anchor member and extends radially outwardly beyondthe outer periphery of said anchor member.
 17. An improved anchorbolting assembly as defined in claim 16 wherein a ring-like gasket iscarried on the front end portion of said anchor member in forwardlylimited abutment with said flange.
 18. An improved anchor boltingassembly for mounting in position within a hole extending from a frontface of and into a support structure and that is adapted to be securedwithin the hole by an adhesive material carried within a destructiblecapsule that has been placed therein which comprises, a longitudinallyextending pipe-like anchor member having means closing-off its back end,a headed bolt having a threaded stem and carrying a bearing platethereon, threaded nut-like means carried on a front end portion of saidanchor member and adapted to rotatably receive a forward end of saidstem therein, stop means carried by the front end portion of said anchormember to initially limit turning advance of said stem within saidnut-like means and with respect to said anchor member when said anchormember is being inserted within the hole, said closing-off means beingadapted to move into pressure engagement with the capsule to fracture itand force the adhesive material along the outer side of the length ofsaid anchor member when said anchor member is introduced into the holeby said threaded stem, said anchor member being adapted to be secured inposition within the hole by the adhesive material, and said stop meansbeing adapted to thereafter be displaced under relative rotationalbackward advancement of said stem within said nut-like means wherebysaid bearing plate may be moved into holding engagement with the frontface of the support structure.
 19. An improved anchor bolting assemblyas defined in claim 18 wherein means is carried by the front end portionof said anchor member for confining flow of the adhesive material tosubstantially the length of said anchor member.
 20. An improved anchorbolting assembly as defined in claim 19 wherein said closing-off meanshas means for facilitating penetration of the capsule.